compiling jdk1.5 code to jdk1.4 byte code

[Rashid Darvesh]

Hi,
i need to know how to convert a code written using jkd1.5 to jdk1.4 compliant byte code. we have somecode written in jdk1.5 and i have to deploy that application in oracle web application server which supports jdk1.4. Please let me know. Also please let me know how to use the ant task to do this.
any help asap is much appreciated
Thanks
Rashid

[miguel lisboa]

just a guess:

i think you can use this with javac
-target <release> Generate class files for specific VM version

[Rashid Darvesh]

i know that javac can be used with target tag to do that. Please let me know some code examples how should i use it. can you also give some tips how to use with ant
Thanks
Rashid

[Ernest Friedman-Hill]

That argument will let you compile JDK 1.4 bytecodes, but only if your code doesn't use any JDK 1.5 features. If you've got code that will only compile with JDK 1.5 then it will only run with 1.5.

[Rashid Darvesh]

Thanks Ernest
So basically that mean if we have a code written with specific jdk1.5 features there is no way we can compile it to jdk1.4 compliant byte code. I have heard of some third party looks like retroweaver. They too have the same condition for this problem
Please let me know
Thanks

[Ernest Friedman-Hill]

I had not heard of Retroweaver before. Sounds like it may help you out! Based on my few moments of looking at the manual, it doesn't sound like it will help you if the code uses any 1.5-specific APIs, but it does emulate essentially all of the new Tiger language features.

[Jeroen Wenting]

tools like retroweaver take your 1.5 compliant Java source and transpile it into 1.4 compliant Java code. This can then be offered to a 1.4 compiler.
I don't know how effective they are, I can imagine some areas where transpilation can be extremely difficult if not impossible.

[Juanjo Bazan]

Originally posted by Jeroen Wenting:
tools like retroweaver take your 1.5 compliant Java source and transpile it into 1.4 compliant Java code. This can then be offered to a 1.4 compiler.
I don't know how effective they are, I can imagine some areas where transpilation can be extremely difficult if not impossible.

Probably that kind of tools depends on the new features of Tiger you are using. If we are talking about generics or autoboxing I think the conversion may be posible, even "just" :roll: recoding / refactoring.
But if you are using Tiger's new packages and advanced classes I would not expect your code to be converted to something 1.4 compilable.

[Jeroen Wenting]

Like I said, some code converts better than other
Of course anything can be transpiled into something else given enough effort, effort that might be large enough to require human intervention and/or the use of large custom libraries to replace non-existent functionality in the language you're transpiling into.